Three-dimensional (3D) printing is a process for making objects by sequential deposition of material, at times under computer control. For example, the objects can be made sequentially by forming multiple layers of material that are joined together to form a 3D object having desired dimensions. A variety of materials can be used, including metal, ceramic, or polymeric materials. 3D printing systems can vary in the method by which a starting material is transformed to print the 3D object. The transformation methods can include melting, sintering, softening, hardening, or liquifying a starting material to form the 3D object. The quality of a 3D object can depend on the processing methodology and conditions for printing the 3D object. For example, the type of material, the temperatures used to perform the transformation, as well as atmospheric conditions surrounding the 3D object during its formation, may influence characteristics of the 3D object. These characteristics may include the shape, roughness, and porosity, of the 3D object. Currently needed are improved 3D printing systems and methods for controlling the characteristics of 3D objects to obtain the requested 3D object.